1. Field of the Invention
Apparatuses consistent with the present invention relate to a reflection-type bandpass filter for use in ultra-wideband (UWB) wireless data communication.
2. Description of the Related Art
As technology of the art related to embodiments of this invention, for example, the technology disclosed in the following references 1 through 12 is known.
Reference 1: Specification of U.S. Pat. No. 2,411,555
Reference 2: Japanese Unexamined Patent Application No. 56-64501
Reference 3: Japanese Unexamined Patent Application No. 9-172318
Reference 4: Japanese Unexamined Patent Application No. 9-232820
Reference 5: Japanese Unexamined Patent Application No. 10-65402
Reference 6: Japanese Unexamined Patent Application No. 10-242746
Reference 7: Japanese Unexamined Patent Application No. 2000-4108
Reference 8: Japanese Unexamined Patent Application No. 2000-101301
Reference 9: Japanese Unexamined Patent Application No. 2002-43810
Reference 10: A. V. Oppenheim and R. W. Schafer, “Discrete-time signal processing,” pp. 465-478, Prentice Hall, 1998.
Reference 11: G-B. Xiao, K. Yashiro, N. Guan, and S. Ohokawa, “An effective method for designing nonuniformly coupled transmission-line filters,” IEEE Trans. Microwave Theory Tech., vol. 49, pp. 1027-1031, June 2001.
Reference 12: Y. Konishi, “Microwave integrated circuits”, pp. 9-11, Marcel Dekker, 1991
However, the bandpass filters proposed in the related art may not satisfy the FCC specifications, due to manufacturing tolerances and other reasons.
Further, bandpass filters having an open construction with the microstrip line exposed are easily affected by external influences.
This invention was devised in light of the above circumstances, and has as an exemplary object the provision of a high-performance UWB reflection-type bandpass filter which is not easily affected by external influences, and which satisfies FCC specifications.